Linux Kernel up to 6.12.20/6.13.8 Efivars Service null pointer dereference

Summaryinfo

A vulnerability, which was classified as critical, was found in Linux Kernel up to 6.12.20/6.13.8. Affected by this vulnerability is an unknown functionality of the component Efivars Service. Such manipulation leads to null pointer dereference. This vulnerability is documented as CVE-2025-21998. There is not any exploit available. You should upgrade the affected component.

Detailsinfo

A vulnerability was found in Linux Kernel up to 6.12.20/6.13.8 and classified as critical. Affected by this issue is some unknown functionality of the component Efivars Service. The manipulation with an unknown input leads to a null pointer dereference vulnerability. Using CWE to declare the problem leads to CWE-476. A NULL pointer dereference occurs when the application dereferences a pointer that it expects to be valid, but is NULL, typically causing a crash or exit. Impacted is availability. CVE summarizes:

In the Linux kernel, the following vulnerability has been resolved: firmware: qcom: uefisecapp: fix efivars registration race Since the conversion to using the TZ allocator, the efivars service is registered before the memory pool has been allocated, something which can lead to a NULL-pointer dereference in case of a racing EFI variable access. Make sure that all resources have been set up before registering the efivars.

The advisory is shared for download at git.kernel.org. This vulnerability is handled as CVE-2025-21998 since 12/29/2024. The exploitation is known to be difficult. There are neither technical details nor an exploit publicly available.

The vulnerability scanner Nessus provides a plugin with the ID 241070 (Ubuntu 24.04 LTS : Linux kernel (OEM) vulnerabilities (USN-7606-1)), which helps to determine the existence of the flaw in a target environment.

Upgrading to version 6.12.21 or 6.13.9 eliminates this vulnerability. Applying the patch c4e37b381a7a243c298a4858fc0a5a74e737c79a/f15a2b96a0e41c426c63a932d0e63cde7b9784aa/da8d493a80993972c427002684d0742560f3be4a is able to eliminate this problem. The bugfix is ready for download at git.kernel.org. The best possible mitigation is suggested to be upgrading to the latest version.

The vulnerability is also documented in the databases at Tenable (241070) and CERT Bund (WID-SEC-2025-0698). Once again VulDB remains the best source for vulnerability data.

Affected

• Google Container-Optimized OS
• Debian Linux
• Amazon Linux 2
• Red Hat Enterprise Linux
• Ubuntu Linux
• SUSE Linux
• Oracle Linux
• Open Source Linux Kernel
• SolarWinds Security Event Manager
• Dell Secure Connect Gateway

Productinfo

Type

• Operating System

Vendor

• Linux

Name

• Kernel

Version

• 6.12.0
• 6.12.1
• 6.12.2
• 6.12.3
• 6.12.4
• 6.12.5
• 6.12.6
• 6.12.7
• 6.12.8
• 6.12.9
• 6.12.10
• 6.12.11
• 6.12.12
• 6.12.13
• 6.12.14
• 6.12.15
• 6.12.16
• 6.12.17
• 6.12.18
• 6.12.19
• 6.12.20
• 6.13.0
• 6.13.1
• 6.13.2
• 6.13.3
• 6.13.4
• 6.13.5
• 6.13.6
• 6.13.7
• 6.13.8

License

• open-source

Website

• Vendor: https://www.kernel.org/

CPE 2.3info

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CPE 2.2info

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Entryinfo

Once again VulDB remains the best source for vulnerability data.

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